Why is it that some buildings (like schools) can be tested for mold and come out “healthy” when many people in the building have moderate to severe SBS symptoms?-Susan , California

 

Part II. 

            As previously indicated (see August 12, 2004 posting) SBS symptoms can be associated with a variety of risk factors.  In the mid 90’s we conducted a questionnaire study of randomly-selected Indiana school teachers.  The prevalence rate for mucous membrane (eye, nose, throat, sinus irritation) and general symptoms (headache, unusual fatigue, lethargy, etc.) was relatively high (circa 20+ %) even after taking non-responders into account.  Respiratory symptoms such as cough, shortness of breath, wheeze, etc. were reported at a rate of about 5.5% which is relatively consistent with the national rate for asthma.  Indeed the highest response rate was from individuals who reported that they had asthma. 

            The questionnaire study revealed a number of potential risk factors.  These included for mucous membrane symptoms moisture/mold problems, ventilation adequacy, dusty surfaces and inadequate cleaning; for general symptoms the same risk factors with the addition of pest problems/pesticide use and for respiratory symptoms the presence of mold odor, ventilation problems, dusty surfaces and inadequate cleaning. 

            After taking into account the potential covariation of some of these risk factors, we observed that the most important risk factors for school-related symptoms (those reported often and always and got better when away from the school building) were moisture/mold problems, inadequate ventilation, and dusty surfaces.  

            As can be seen moisture/mold was a significant risk factor for SBS symptoms among school teachers.  However, it is not the only factor.  Inadequate ventilation and dusty surfaces were factors as well.  Inadequate ventilation is a common cause of complaints in school buildings.  In my personal experience, headaches and fatigue are commonly reported when ventilation is poor.  However, our studies also showed that mucous membrane symptoms were also significantly associated with poor ventilation. 

            The reported relationship between SBS symptoms and dusty surfaces/inadequate cleaning is interesting as a number of studies indicate that dust and components of dust are major risk factors for SBS symptoms.  Among these components are allergens from cats, dogs and cockroaches. 

            In another study conducted in Indiana schools, we observed significant levels of cat and dog allergens in floor dust of elementary school buildings.  Allergen levels were in a number of cases in the range that posed on exposure a risk for developing allergy-type (mucous membrane) symptoms and in some rarer cases a risk of sensitization.  What was the source of these cat and dog allergens?  Passive transport from homes on the clothes of children and staff.

August 20, 2004

 

 

Indoor Environmental Quality (2000), Thad Godish Ph.D., C.I.H

Direct E-mail 00tjgodish@bsu.edu